1. Technical Field
The present invention relates to an input device and to a personal mobile terminal having the same.
2. Description of Related Art
FIG. 13 is a front view of a personal mobile terminal having a conventional input device.
As shown in FIG. 13, a conventional personal mobile terminal 100 is a so-called mobile phone, and is integrally composed of an operation unit 101 as an input device for inputting a telephone number and the like. In addition to this, the personal mobile terminal device 100 is composed of: a display unit 102 for displaying various kinds of information; and a speaker 103 and a microphone 104 used for a telephone conversation.
The operation unit 101 of the personal mobile terminal 100 includes input keys, function keys, selection keys, and an enter key.
The input keys include twelve kinds of keys which are: ten numeric keys on which numeric characters 0 to 9 are respectively labeled; and two auxiliary keys on which * and # are respectively labeled.
The function keys are used for calling functions, such as “clear”, “memo”, and “manner mode”.
The enter key is used for having a next process performed on the basis of information inputted from the input device.
When an operator of the personal mobile terminal 100 operates the personal mobile terminal 100 with a hand, the operator typically holds the personal mobile terminal 100 in one hand and operates the input device with the thumb of the hand holding the personal mobile terminal 100. To be more specific, the operator uses the thumb of the hand holding the personal mobile terminal 100 to operate the input keys, the function keys, the selection keys, and the enter key.
FIG. 14 is a diagram for explaining a load put on the thumb during operation of the personal mobile terminal 100 having the conventional input device.
The keys provided for the conventional personal mobile terminal 100 are not arranged in consideration of a region which allows for easy movement of the finger that is used for operation. More specifically, all the keys including the numeric keys provided for the input device are the same in size and are just arranged in a matrix in an orderly manner.
When the numeric keys of the personal mobile terminal 100 as described above are operated with the thumb, a load on the thumb is relatively light when operating the keys in a region A apart from the base of the thumb whereas a heavy load is put on the thumb when operating the keys in a region B close to the base of the thumb. On account of this, the more the number of key operations, the heavier the load put on the hand and the finger used for operation. This load is considered as a possible cause of mental and physical fatigue. In addition, in the case where the fatigue has built up on the hand and the finger, the personal mobile terminal may be dropped and damaged, such as when the operator tries to get a better grip on the personal mobile terminal.
This problem has remarkably arisen as the number of key operations has been increased along with multi-functionality of personal mobile terminals of recent years. Especially in terms of character input operations such as an email creation, an increase in the number of characters allowed in an email transmission significantly increases the number of key operations. For this reason, it is highly possible to cause mental and physical fatigue, and this problem thus should be solved as soon as possible.
In order to solve this problem, terminals with easy operability that reduce the load on the hand and the finger used for operation have been suggested (see JP2002-164980 and JP 2001-296953, for example).
FIG. 15 is a diagram showing a conventional personal mobile terminal described in mentioned above.
As shown in FIG. 15, a plurality of keys 18 are arranged along circumferences of circles having the same center which is described as a predetermined point O. Consider a case where a body 11 is held with a palm of one hand and fingers other than a thumb of this hand, and key operations are performed using only the thumb of the hand. By aligning the predetermined point O with the center of the joint at the base of the thumb, the keys 18 come to be situated along paths of rotational movements made by the thumb with the joint being the center. This key arrangement allows for an improvement in the operability of key inputs performed for inputting characters or symbols.
FIG. 16 is a diagram showing a personal mobile terminal having a conventional input device described in mentioned above.
As shown in FIG. 16, a button key unit 600 and a jog dial unit 700 are structured separately so as to each rotate freely on a center of a circle as its axis of rotation. The separate rotations of the button key unit 600 and the jog dial unit 700 substantially increase the amount of information allowed to be inputted. In addition to this, a reduction in a surface area occupied by the button key unit 600 and the jog dial unit 700 decreases the amount of movements made by a finger of the operator since an input operation can be performed in this small area. Thus, the operator is able to perform an efficient operation.
Patent Reference 1: Japanese Laid-open Patent Application No. 2002-164980
Patent Reference 2: Japanese Laid-open Patent Application No. 2001-296953